Acetylene, an important petrochemical raw material, is very difficult to store safely under compression because of its highly explosive nature. Here we present a porous metal-organic framework named FJI-H8, with both suitable pore space and rich open metal sites, for efficient storage of acetylene under ambient conditions. Compared with existing reports, FJI-H8 shows a record-high gravimetric acetylene uptake of 224 cm3 (STP) g−1 and the second-highest volumetric uptake of 196 cm3 (STP) cm−3 at 295 K and 1 atm. Increasing the storage temperature to 308 K has only a small effect on its acetylene storage capacity (∼200 cm3 (STP) g−1). Furthermore, FJI-H8 exhibits an excellent repeatability with only 3.8% loss of its acetylene storage capacity after five cycles of adsorption–desorption tests. Grand canonical Monte Carlo simulation reveals that not only open metal sites but also the suitable pore space and geometry play key roles in its remarkable acetylene uptake.

Reticular chemistry offers the possibility of systematic design of porous materials with different pores by varying the building blocks, while the emerging porous organic cage (POC) system remains generally unexplored. A series of new POCs with dimeric cages with odd−even behaviors, unprecedented trimeric triangular prisms, and the largest recorded hexameric octahedra have been prepared. These POCs are all constructed from the same tetratopic tetraformylresorcin[4]arene cavitand by simply varying the diamine ligands through Schiff-base reactions and are fully characterized by X-ray crystallography, gas sorption measurements, NMR spectroscopy, and mass spectrometry. The odd−even effects in the POC conformation changes of the [2 + 4] dimeric cages have been confirmed by density functional theory calculations, which are the first examples of odd−even effects reported in the cavitand-based cage system. Moreover, the "V" shape phenylenediamine linkers are responsible for the novel [3 + 6] triangular prisms. The window size and environment can be easily functionalized by different groups, providing a promising platform for the construction of multivariate POCs. Use of linear phenylenediamines led to record-breakingly large [6 + 12] truncated octahedral cages, the maximum inner cavity diameters and volumes of which could be readily modulated by increasing the spacer length of the phenylenediamine linkers. This work can lead to an understanding of the self-assembly behaviors of POCs and also sheds light on the rational design of POC materials for practical applications.

The effective capture and storage of volatile radionuclide iodine from the nuclear waste stream is of paramount importance for environment remediation. In this work, we report the first examples of azo-bridged calix[4]resorcinarene-based porous organic frameworks (CalPOFs), synthesized by diazocoupling reaction of 4,4′-biphenyldiamine and C-alkylcalix[4]resorcinarenes (RsC n s; n stands for the associated alkyl chain length) under mild conditions. The resulting CalPOFs are permanently porous, and their porous properties could be adjusted by varying the alkyl chain lengths of RsC n s. With the alkyl chain length increasing from methyl, ethyl to propyl, the Brunauer−Emmett−Teller surface areas are decreasing from 303, 154 to 91 m 2 g −1 for CalPOF-1, CalPOF-2 and CalPOF-3, respectively. The presence of a great many of effective sorption sites including azo (−NN−) groups, macrocyclic π-rich cavities and phenolic units in the skeleton as well as permanent porous structures provides these materials with ultrahigh iodine vapor uptake up to 477 wt %. Further, thorough studies revealed that the capacities for removing iodine vapor are in the order of CalPOF-1 (477 wt %) > CalPOF-2 (406 wt %) > CalPOF-3 (353 wt %), which are dependent on their surface areas, and also the densities of the azo and RsC n units. In addition, detailed analyses of iodine-loaded CalPOF-1 suggested that chemisorption is the major process in this adsorbent, illustrating the big chance to explore versatile CalPOFs to capture volatile toxic vapors.

The removal of ethane (C2H6) from its analogous ethylene (C2H4) is of paramount importance in the petrochemical industry, but highly challenging due to their similar physicochemical properties. The use of emerging porous organic cage (POC) materials for C2H6/C2H4 separation is still in its infancy. Here, we report the benchmark example of a truncated octahedral calix[4]resorcinarene-based POC adsorbent (CPOC-301), preferring to adsorb C2H6 than C2H4, and thus can be used as a robust absorbent to directly separate high-purity C2H4 from the C2H6/C2H4 mixture. Molecular modelling studies suggest the exceptional C2H6 selectivity is due to the suitable resorcin[4]arene cavities in CPOC-301, which form more multiple C–H···π hydrogen bonds with C2H6 than with C2H4 guests. This work provides a fresh avenue to utilize POC materials for highly selective separation of industrially important hydrocarbons.

Research into stimuli-responsive controlled self-assembly and reversible transformation of molecular architectures has received much attention recently, because it is important to understand and reproduce this natural self-assembly behavior. Here, we report two coordination nanocapsules with variable cavities: a contracted octahedral V24 capsule and an expanded ball-shaped V24 capsule, both of which are constructed from the same number of subcomponents. The assemblies of these two V24 capsules are solvent-controlled, and capable of reversible conversion between contracted and expanded forms via control of the geometries of the metal centers by association and dissociation with axial water molecules. Following such structural interconversions, the magnetic properties are significantly changed. This work not only provides a strategy for the design and preparation of coordination nanocapsules with adaptable cavities, but also a unique example with which to understand the transformation process and their structure-property relationships.

The self-assembly of cationic tetranuclear-metal building blocks generated in situ based on p-tertbutylthiacalix[4]arene and linear anionic ligands (1,4-benzenedicarboxylic acid) gave rise to an anionic truncated octahedral coordination cage through a [6 + 12] condensation. This research provides a new building block with unique geometry to construct coordination cages with multifunctional properties.

Photo-assisted Li-organic batteries provide an attractive approach for solar energy conversion and storage, while the challenge lies in the design of high-efficiency organic cathodes. Herein, a charge-separated and redox-active C60@porous...

Multiple orthogonal coordinative interactions were utilized to construct heterometal-decorated tetrahedral cages from in situ formed trinuclear Zr clusters through the combination with other metal ions such as Cu or Pd . Through effective use of the hard/soft acid/base principle, the orthogonal self-assembly process of Zr-bpydc-CuCl (H bpydc=2,2-bipyridine-5,5-dicarboxylic acid) can be finely controlled using three strategies: post-synthetic metallization, a stepwise metalloligand approach, or a one-pot reaction.